[cinchcast] Add new extractor (Fixes #4428)

youtube_dl/extractor/__init__.py

@@ -51,6 +51,7 @@ from .cbsnews import CBSNewsIE
 from .ceskatelevize import CeskaTelevizeIE
 from .channel9 import Channel9IE
 from .chilloutzone import ChilloutzoneIE
+from .cinchcast import CinchcastIE
 from .clipfish import ClipfishIE
 from .cliphunter import CliphunterIE
 from .clipsyndicate import ClipsyndicateIE